>> How do I upgrade my SQL Management Studio Express 2005 to the 2008 version?
>> Do I completely uninstall 2005, then install the new version?

There is no way to Upgrade SSMSE 2005 to SSMSE 2008..
You need to uninstall SSMSE 2005 and then install SSMSE 2008.

>> Do I simply install 2008 over the top of 2005?
Will I end up with conflicts and both versions running side-by-side if I don't uninstall 2005 first?

If you install SSMSE 2008 with SSMSE 2005 existing in your machine, then you will end up having both of them in your machine..
And there wont be any conflicts arising out of that..
Using SSMSE 2005, you can connect to SQL Server 2000 and 2005 databases.
And Using SSMSE 2008, you can connect to SQL Server 2000, 2005 and 2008 databases.

Featured Post

As a web developer or IT admin, successfully managing multiple client accounts can be challenging. In this webinar we will look at the tools provided by Media Temple and Plesk to make managing your clients’ hosting easier.

What if you have to shut down the entire Citrix infrastructure for hardware maintenance, software upgrades or "the unknown"? I developed this plan for "the unknown" and hope that it helps you as well. This article explains how to properly shut down …

Using examples as well as descriptions, and references to Books Online, show the documentation available for date manipulation functions and by using a select few of these functions, show how date based data can be manipulated with these functions.